1. Field of the Invention
The present invention relates to a drawing apparatus, and a method of manufacturing an article.
2. Description of the Related Art
As one of apparatuses employed in a process of manufacturing, for example, a semiconductor device (lithography process), a so-called multiple charged particle beam drawing apparatus (charged particle beam exposure apparatus) which draws (transfers) a pattern on a substrate with a plurality of charged particle beams has been proposed in the International Publication No. 2009/127659.
The drawing apparatus controls blanking of each of a plurality of charged particle beams (switching between ON and OFF of the irradiation of the substrate) in accordance with a pattern (drawing pattern) to be drawn on the substrate by a blanker (blanking deflector array), thereby drawing the pattern on the substrate. Also, ON/OFF of the irradiation of the substrate with the charged particle beams is generally controlled for each drawing grid (one charged particle beam drawing range). Therefore, a blanking control unit supplies (transmits) a control signal for controlling a blanking deflector to the blanking deflector via an optical communication fiber for each drawing grid.
A communication unit provided in a blanking deflector BD receives a blanking deflector control signal, as shown in FIG. 5. The communication unit includes a photodiode 1021, transfer impedance amplifier 1022, limiting amplifier 1023, and serial/parallel converter (SERDES) 1024. A control signal (optical signal) from the fiber is received by the photodiode 1021, is converted from a current into a voltage by the transfer impedance amplifier 1022, and undergoes amplitude control by the limiting amplifier 1023. A signal from the limiting amplifier 1023 is input to the SERDES 1024 and converted from a serial signal into a parallel signal.
A transistor (FET) 1033 is placed at the intersection between a horizontally running gate electrode line and a vertically running source electrode line, and two bus lines are connected to the gate and source of the FET 1033, as shown in FIG. 5. The FET 1033 has its drain connected to an electrode 1035 and capacitor 1034 of the deflector, and has a common electrode on the side opposite to these two capacitive elements. With this arrangement, an active-matrix driving type blanking deflector which uses an FET as a switch can simultaneously apply voltages to a large number of FETs via gate electrode lines, thus increasing the number of electrodes while the number of lines is kept small.
However, in a multiple charged particle beam drawing apparatus, as the number of charged particle beams and the drawing frequency increase, the data rate of a control signal transmitted from an optical communication fiber to a blanking deflector rises. To draw a drawing pattern having a half pitch of 22 nm on, for example, 10 or more substrates per unit time, optical communication fibers which exhibit a transmission rate of 10 Gbps are necessary to form 5,000 or more channels (ch). Also, a communication unit provided in a blanking deflector normally consumes a power of several mW/Gps/ch. Therefore, when optical communication fibers which exhibit a transmission rate of 10 Gbps are necessary to form more than 5,000 channels (ch), the communication unit consumes a power of at least 50 W or more and, normally, several hundred watts. A blanking deflector is placed in a lens barrel of a charged particle optical system (electron optical system) which guides a charged particle beam onto a substrate. The interior of the lens barrel of the charged particle optical system is maintained in a high-vacuum environment, and therefore has a limit in the space which can be equipped with a cooling structure. This makes it difficult to remove heat generated by the communication unit in an amount corresponding to a power consumption of several hundred watts. As a result, the heat generated by the communication unit may produce geometric strain (distortion) in the blanking deflector (electrode) to a degree that cannot be ignored in terms of drawing accuracy.